Justification:Ctenochaetus binotatus is widely distributed and is common and abundant in parts of its range. It is harvested for food and for the aquarium trade but not at high levels. There are no major threats known. It is found in a number of marine reserves in parts of its distribution. It is therefore listed as Least Concern.

Ctenochaetus binotatus is widespread in the Indo-Pacific from East Africa to the Tuamoto archipelago and Mangareva, northwards to southern Japan, and southwards to Elizabeth and Middleton reefs with juveniles ranging to Sydney, New South Wales. It is absent from the Line and Marquesan Islands.

Ctenochaetus binotatus is common and locally abundant in the Philippines (R. Abesamis and C. Nanola pers. comm. 2010). It was recorded as common in terms of relative abundance in Palawan, Philippines, Milne Bay Province, northern Bismarck Sea, Papua New Guinea and Raja Ampat, Indonesia (Werner and Allen 2000; Palawan Council for Sustainable Development unpub. data; Allen, 2003, 2003b, 2009). It is common in the American Samoa National Park (National Park of Samoa Checklist of Fishes accessed 21 April 2010).

The genus Ctenochaetus feed on fine detrital material. They whisk the sand or rocky substratum with their teeth and utilize suction to draw in the detrital material that consists of diatoms, small fragments of algae, organic material and fine inorganic sediment (Randall and Clements 2001). On the Great Barrier Reef, this species is generally found deeper than C. striatus. Juveniles are associated with rubble substrata (K.D. Clements pers. comm. 2010). Species of Ctenochaetus share the presence of a thick-walled stomach (Randall and Clements 2001), this character is significant with respect to the nutritional ecology of this genus (Choat et al. 2002b).

Growth

Off Lizard Island, in the northern GBR, otolith increment counts suggests a larval period of 47 to 74 days. The growth rate of this species decreased after settlement (Lou 1993). A maximum age of 25 years was recorded from the Great Barrier Reef and length of 15.1 cm (TL) (J.H. Choat pers. comm. 2010).

Ctenochaetus binotatus is a component of the marine aquarium trade. Online prices range from $34.95-$59.99 per individual (L. Rocha pers. comm. 2010). It is a targeted food fish in western Thailand (Allen 2005). It is rare in the Guam fishery (J. McIlwain pers. comm. 2010).

Surgeonfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reef while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. The majority of surgeonfishes are exclusively found on coral reef habitat, and of these, approximately 80% are experiencing a greater than 30% loss of coral reef area and degradation of coral reef habitat quality across their distributions. However, more research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species' populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that recruit into areas with live coral cover, especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats (Comeros-Raynal et al. 2012).